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<br />i <br /> <br />Worksheet 3: Time of couceotratioo (Tc) or travel time (Tt) <br />Project: CASTLE ROCK QUARRIES <br />Location: Douglas County, Colorado <br />Condition: Post mining <br />Calculations for: Tc <br />NOTES: <br />r <br />L: <br />Sheet Flow (Applicable to Tc onlvl Segment <br />1. Surface description (table 3-1) ......................................... <br />2. Manning's roughness coeff., n (table 3-1 ) ........................ <br />3. Flow length, L (total L c= 300 ft.) ..................................... <br />4. Two-yr 24-hr rainfall, P2 ................................................... <br />5. Lantl slope, s ................................................................... <br />6. Tt=[0.007 (nL)"(0.8)y[P2"(0.5) s^(0.4)] Compute Tt........ <br />By: 7PY Dale: <br />Checked: JGJ Date: <br />BASIN G <br />7/21 /95 <br />7/21 /95 <br />0.07 <br /> <br />r Sha llow concentrated flow Segment ID <br /> 7. Surface description (paved or unpaved) ....................... ... <br /> 8. Flow length, L .............................................................. .... ft <br />' 9. Watercourse slope, s ................................................... .... fl/ft <br /> 10. Average velocity, V (figure 3-1) .................................... .... ft/s <br /> 11. Tt = U(3600 V) Compute Tt..... .... hr <br />Shallow concentrated flow (continued) Segment IC <br />7. Surface description (paved or unpaved) .......................... <br />6. Flow length, L .................................................................. <br />9. Watercourse slope, s ....................................................... ft/ <br />10. Average velocity, V (figure 3-1) ........................................ ft <br />11. Tt = U(3600 V) Compute Tt......... I <br /> <br /> Ch annel flow Segment ID <br /> 12. <br />13. Cross sectional Flow area, a ....................................... <br />Wetted perimeter. Pw .................................................. ..... ft^2 <br />..... ft <br /> 14. Hydraulic radius, r =a/pw Compute r...... ..... ft <br /> 15. Channel slope, s ......................................................... ..... fl/ft <br /> 16. <br />17. Manning's roughness weff., n ..................................... <br />V = (1.49 r"(2B) s"(1/2))/n Compute V........ .... <br />.... fl/s <br /> 16. Flow length. L ............................................................ ..... fl <br /> 19. Tl = U(3600 V) Compute Tt...... ..... hf <br /> <br /> 20. Watershed or subarea Tc or Tt (add Tl in steps 6, 11, and 19) ............. <br />i <br /> <br /> <br />(210-V1-TR-55, Second Ed., June 1986) <br />T2 T3 <br />6 6 <br />7.83 7.83 <br />0.77 0.77 <br />0.0471 0.0419 <br />0.035 0.035 <br />7.74 7.30 <br />806 1479 <br />0.03 0.06 <br />0.09 <br />hr 0.16 <br />~~ <br />